The short range wireless communication performing non-contact wireless communication at close range of about several centimeters is employed in electronic commuter passes and electronic money, for example. Mobile phones equipped with the electronic commuter pass and electronic money functions using the short range wireless communication are also becoming widespread. The short range wireless communication is standardized in ISO/IEC 14443 and ISO/IEC 18092 (hereinafter also referred to as an NFC (Near Field Communication)), for example.
The short range wireless communication performed at a higher transmission rate than the NFC is becoming popular as well. TransferJet (registered trademark) is a communication scheme of such high-speed, short range wireless communication, for example. TransferJet (registered trademark) is the short range wireless communication scheme using an ultra wide band (UWB) (refer to Patent Document 1, for example), and is standardized in ISO/IEC 17568 and ISO/IEC 17569. TransferJet (registered trademark) adopts a carrier of 4.48 GHz and performs the short range wireless communication at the transmission rate of 560 Mbps maximum.
The short range wireless communication scheme like TransferJet (registered trademark) enables high-speed data transfer among devices such as a digital camera, a personal computer (PC) and a printer (refer to Patent Document 2, for example). A short range wireless communication system employing such short range wireless communication scheme uses an antenna based on electric field induction to facilitate detection of only the party at the other end present nearby as well as deliberately limit the communication range to the close range of several centimeters and ensure security for the range, whereby complicated security setting is not required while at the same time improving usability (moderate feel of a touch operation) for a user, the antenna providing attenuation of radio waves emitted therefrom in proportion to the fourth power of the distance.
Moreover, there has been an attempt in recent years to perform faster data transfer by using a wide range of frequencies in a millimeter wave band. Radio waves attenuate in proportion to the square of the frequency, so that the low-gain antenna based on the electric field induction cannot be used for the high-frequency millimeter wave. It is thus considered appropriate for radio wave communication using the millimeter wave to use a normal antenna with which the radiated waves attenuate in proportion to the square of the distance.